Dream detection method and system

ABSTRACT

The present invention relates to a dream retrieval method and system including the physiological monitoring of a sleeping subject, the analysis of recurring behavioral parameters, the application of suitable algorithms to the observed parameters and, subject stimulation in response to algorithm deductions. In the preferred embodiment, gross body motions and postural changes are both analyzed in magnitude and regularity. Upon recognizing recurring body motions indicative of a dream cycle, the device establishes a time window during which the completion of the next dream should occur. If physiological behavior indicative of dreaming is discovered within the time window, the subject is awakened. As a result of this timely awakening, the subject obtains greater dream recall than is normally possible and may optionally record dream content.

BACKGROUND OF THE INVENTION

A. Field of the Invention

This invention relates to increasing dream recall and more specificallyto increasing dream recall by awakening a subject immediately after adream.

B. Background Art

Throughout the period of sleep, humans typically experience dreamperiods. Dream periods (REM) comprise approximately 15%-20% of theevening's sleep and occur with regularity every 80-100 minutes. Whilethe subject is asleep, however, the body continues to exhibit manycharacteristic physiological changes. Although most of these changes arereadily monitored and calibrated, the preferred embodiment focuses onthe subject's motor activity which occurs during sleep. For instance,during sleep there are frequent gross body movements or posturalchanges. These shifts in position occur with increased frequency beforeand after dream periods, whereas a period of simulated paralysis occursduring the dream period proper. As a specific example, during humansleep there is a period of increased motor activity before a dream, aperiod of relative immobility during the dream, and increased motoractivity following the dream. This behavior is then repeated 80-100minutes later. Prior art, such as "Ethology of Sleep Studied withTime-Lapse Photography: Postural Immobility and Sleep-Cycle Phase inHumans" by Hobson in Science, Vol. 201, 1978, pp 1251-1253, includes theanalysis of postural changes during sleep and acknowledges theregularity of dreaming but, never has a means for the utilization andcalibration of gross body movements in predicting dream occurrences beendisclosed. This is also discussed in Advances in Dream Research byElliot Weitzman, Spectrum Publications, 1976.

During an average sleeping period, the sleep-dream cycle repeats 4-6times as noted in "Every 90 Minutes, A Brainstorm" by Michael H Chase,Psychology Today, November 1979, p. 172. The percentage of dreamsrecalled and the accuracy with which they are recalled varies betweenindividuals but, dream content is usually forgotten unless theindividual has been awakened or disturbed during the dream. Toeffectively capture dream content it is therefore desirable to awaken asubject at the conclusion of his dream as recognized in Sleep andDreaming by David B. Cohen, A. Wheaton and Co., Ltd., 1979.

Many prior patents have been obtained for the awakening of a subject inresponse to the monitoring of brain wave activity which would indicatethat a subject is falling asleep. These systems have obvious use in theawakening of a dozing driver or the monitoring of patients in anintensive care situation. U.S. Pat. No. 4,228,806 discloses a devicewhich inhibits wake-up alarms during deeper phases of sleep; thusfunctioning as an alarm clock accessory which prevents the subject frombeing aroused from a deep sleep. There is no attempt, however, in theseprior art arrangements to address dream retrieval or a means ofautomated calibration or correlation of gross body movements found nearand about dream periods.

Obvious to those in the field is the possible alteration of dreamcontent by the introduction of physical stimuli to a dreamingindividual. Prior art includes devices which dictate suggestions tosleeping individuals at some predetermined time into the period ofsleep. However, these devices do not calculate when the subject isdreaming and only provide for random application of subject stimuli. Seefor example "Lucid Dreaming" by Stephen LaBerge in Psychology Today,January 1981, pp. 48-57.

British Pat. No. 1,215,904 and U.S. Pat. No. 4,420,011 disclose deviceswhich measure increased respiration during "unpleasant dreams," afterwhich, an attempt is made to bring the subject to a higher level ofconsciousness where they might experience a more "lucid" dream. Thesereferences lack the correlation of findings from earlier in the sleepingperiod to more recent subject behavior in the predicting and ultimateretrieval of their dreams.

Motion sensors function in various systems and devices not related tohuman movement. U.S. Pat. Nos. 4,381,504 and 4,450,326, both disclosedevices which establish electrical continuity across two or moreterminals when translated or displaced. However, neither of theseembodiments measure or correlate the intensity of sound produced duringthe actual motion. U.S. Pat. No. 3,955,562 depicts a device formeasuring the degree of positional change found in normal human movementbut pertains only to the connection of electrical contacts by thedepression of switches or translation of electrically conductive fluid.

BRIEF DESCRIPTION OF THE INVENTION

The present invention provides a method and system for confirming theoccurrence of dream behavior in a sleeping subject. The subject ismonitored for an initial occurrence of physiological behavior indicativeof dream sleep. After apparent dream behavior is recognized, a waitperiod, equal to the typical duration between two successive dreams, isinitiated. After this period, a recurrence of previous dream behavior issought. Upon detecting the second occurrence of the dream behavior, thepresent invention confirms the occurrence of a dream cycle.

More particularly, the present invention embodies a dream retrievalsystem for analyzing gross body movements, calculating dream periods,extrapolating from these periods projected dream occurrences, andfinally awakening the subject upon the conclusion of a dream. A furtherembodiment provides methods of dream alteration or enhancement. Physicaland/or auditory stimuli may optionally be given to the subject once adream occurrence has been established in an attempt to constructivelyinterfere with dream content. The auditory stimuli may include a tone orpulse in the audible frequency range of sufficient volume to be heard bythe subject. This dream enhancement function will hereinafter bereferred to as "the suggester". The suggester may be a tape player or asiren.

Motion sensors, attached to the subject or sleeping surface, detect bodymotion and using a short-range transmitter relay information to areceiver where they are calibrated, qualified, and then forwarded to theinput port of a computation device. Once the motions have been encoded,the train of pulses is searched and analyzed for periods of increasedmovement frequency. Once increased movement frequency indicative ofpre-dream conditions is noted, a period of relative immobility followedby motions indicative of a post-dream condition are searched for. Ifthese conditions are satisfied, an apparent dreaming epoch has occurred.A sleep-dream cycle is confirmed if a recurrence of these motionconditions occurs 80-100 minutes later. After this confirmation, dreammanipulation may be performed followed by subject awakening. A taperecorder may be supplied at the sleep site for the subject to recorddream content.

The parameters which qualify a group of motions as being eitherpre-dream or post-dream in nature may be adjusted to best satisfy theparticular characteristics of the individual. In addition, the dreamenhancement routines which physically prompt and stimulate the sleepingsubject, operate independent from the post-dream awakening mechanism.Hence, these are optionally engaged or interchanged, depending on thesubject's favor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A,B are block diagrams which illustrate the determination ofdream periods by applying typical dream recurrence parameters.

FIG. 2 is a pictorial representation of hardware devices of thepreferred embodiment of the invention of FIGS. 1A,B.

FIGS. 3A,B illustrate the preferred embodiments of the motion sensor andits appropriate means of attachment to the subject.

FIG. 4 is a flow chart which shows the logic of a FORTRAN program whichimplements the preferred embodiment.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIGS. 1A,B there is shown block diagrams of the dreamretrieval system of the present invention. System 8 is essentiallygeared toward accurately predicting dream periods by detectingphysiological behavioral patterns. System 8 divides each dream eventinto three separate units; pre-dream sleep, dream sleep, and post-dreamsleep. The system evaluates each unit independently and anticipatesphysiological behavior unique to that phase of sleep.

At start block 12, system 8 allows the subject to fall asleep. This isexecuted by either allotting the subject a predetermined period of timeto fall asleep or by awaiting certain physiological conditions whichindicate that the subject is asleep. System 8 searches at block 14 forsubject behavior parameters indicative of pre-dream sleep. Physiologicalpre-dream behavior parameters may include, for example, increasedbrain-wave activity, moderate increases in respiration, increased muscletonus, and increased limb movement in connection with postural shiftsand gross body motions. Once the pre-dream behavior of block 14 isestablished, optionally the pre-dream routine of block 28 may beengaged. This routine may contain, for example, an alarm or otherstimuli to awaken the subject, thus enabling dream deprivation or theexploration of other various pre-dream fields of interest.

Control is then transferred to block 16 where a determination is madewhether the subject is dreaming. Physiological conditions, indicative ofdreaming may include, for example, rapid eye movements (REM), increasedrespiration rates, electro-neural activity, muscle tonus, extremitytwitching, and simulated spinal paralysis. Once dreaming behavior ofblock 16 has been established, optionally, the dream routine of block 32may be engaged. This routine may contain, for example, a dreamenhancement mode which would attempt to alter or contaminate a subject'sdream through the introduction of pseudo-hypnotic suggestion or sleepingenvironment manipulation. Other dream routines might include, forexample, a "lucid" dream inducer or a mid-dream interrupter. Inaddition, physical promptings and possible methods of bio-feedback,incorporating monitored physiological responses, may also be employed,as they might also affect dream content. After such intervention thesubject may optionally be awakened or allowed to continue sleeping.

Control is then transferred to block 18 where a determination is madewhether the subject is experiencing post-dream sleep. Physiologicalconditions indicative of post-dream sleep may include, for example, anabrupt drop in electro-neural activity, decreases in respiration rates,and a rebound or increase in limb movements possibly accompanied bypostural shifts and gross body motions. Once the post-dream behavior inblock 18 has been established, the post dream routine of block 36 may beengaged. In the embodiment of dream retrieval system 8 the subject isawakened upon dream completion, thus permitting dream recall. Thesubject may then verbally or otherwise record dream content on a taperecorder (not shown). Furthermore, upon acknowledging the completion ofthe dream at block 18, system 8 may implement bio-feedback methods topossibly lengthen the dream itself.

Control is then transferred to block 37 where system 8 confirms that adream event has transpired. System 8 may terminate at block 38 or mayreturn to start block 12.

It should be noted, that in establishing an apparent dream event someblocks of FIG. 1A may be omitted. For example, a dream event may beestablished on the basis of the pre-dream sleep behavior determined inblock 14 and/or the post-dream sleep behavior determined in block 18. Inthis case, system 8 can still confirm the dream event at block 37without recognition of the subject's physiological behavior during thedream period at block 16. This ability becomes especially useful whenmeasuring gross body movements during sleep, as there are nocharacteristic body movements inherent in dream sleep. In this case,block 16 is bypassed. Further, by way of lines 15, 17, and 19 if thecorresponding conditions of blocks 14, 16, and 18, respectively, are notsatisfied, control is returned to start block 12 and the current dreamevent that system 8 was tracking is invalidated.

Referring to FIG. 1B there is shown a block diagram of dream retrievalsystem 10 in which a method for confirming the dream determined bysystem 8 is provided. This method for confirming the occurrence of adream is based upon the cyclical nature of dream behavior.

System 10 which is the preferred embodiment of the present inventionuses the same behavioral patterns to determine dream periods as system 8but, including a calibration function which identifies a recurrence ofthe dream cycle. As in system 8, blocks 14, 16, 18 search for pre-dream,mid-dream and post-dream physiological behavior respectively. System 10,however, does not immediately engage routines 28, 32, and 36 aspreviously described for system 8. Instead of confirming the dream eventimmediately after the post-dream behavioral parameters are observed inblock 18, at block 20 an apparent dream is determined and theconfirmation of a dream event in block 37 is not performed until laterin the sleep period.

When an apparent dream event is established at block 20, an appropriatewaiting period is initiated at block 22. This "waiting period" and allother timing parameters relative to block 22 are obtained fromperipheral clock 23. Since dreams recur in a cyclic fashion, system 10allows time for the non-dream phases of sleep to transpire. Therefore,system 10 does not anticipate a recurrence of an apparent dream event,as found in block 20, until later in the sleep cycle. Therefore, a timewindow is established approximately 80 to 100 minutes after thedetermination of an apparent dream event in block 20. Hence, after 80minutes, system 10 expects another dream event which physiologicallyresembles the first apparent dream event detected at block 20. After 100minutes, however, if system 10 has not detected a second dream event,the window ends and control returns to start block 12, as the dreamsleep parameter has expired. During this wait period, however, system 10may engage deep-sleep stimuli or physical promptings as the subject isstill being monitored and thus may still interact with the machine.

After waiting 80 minutes in block 22, control is transferred to restartblock 24 where the search for a dream event recurrence begins. At block26, a determination is made whether the subject is experiencingpre-dream sleep. Physiological conditions that would indicate pre-dreamsleep include those conditions observed as pre-dream behavior at block14. If pre-dream behavior is detected at block 26 and, since the subjecthas demonstrated recurring physiological behavior; pre-dream sleep isconfirmed. Optionally, at block 28 the pre-dream routine previouslydescribed in system 8 may be engaged.

Once the pre-dream behavior of block 26 is established, control istransferred to block 30 where a determination is made whether thesubject is experiencing dream sleep. Physiological conditions thatindicate dream sleep include those observed as recurrent from dreambehavior at block 16. If dream behavior is detected at block 30 and,since the subject has demonstrated recurring physiological behavior;dream sleep is confirmed. Optionally, at block 32 the dream routinepreviously described in system 8 may be engaged.

Once the dream behavior of block 30 is established, control istransferred to block 34 where a determination is made whether thesubject is experiencing post-dream sleep. Physiological conditions thatindicate post-dream sleep include those observed as recurrent frompost-dream behavior at block 18. If post-dream behavior is noted atblock 34 and, since the subject has demonstrated recurring physiologicalbehavior; post-dream sleep is confirmed. Optionally, at block 36 thepost-dream routine described in system 8 may be engaged.

After the completion of the post-dream routine in block 36, system 10determines at block 37 that a confirmed dream event has transpired.Subsequently, system 10 ends at block 38. Here, since the subject hasbeen aroused, system 10 may be entirely aborted or control may simplyreturn to start block 12. If, however, the subject is only mildlyaroused, control may simply return to block 22, as a dream event similarto that in block 20 has just been confirmed at block 37.

It should also be noted that by way of lines 27, 31, or 35 if theconditions of blocks 26, 30, or 34, respectively, are not satisfied,then an entire dream event as in block 20 is not confirmed and controlis transferred to restart 24. Further, if control is still at block 24when the time of block 22 exceeds minute 100, a start is instituted atblock 12, as the recurrence parameter was exceeded.

Referring to FIG. 2 there is shown the preferred physical arrangement ofthe hardware devices of dream retrieval system 40. Subject 42, in themanner one might wear a bracelet or bandage, has fastened to forearm 44and calf 46 sensor bands 48 which detect subject motion. Sensor bands 48relay to a conventional receiver 52 information pertaining to the motionof subject 42. Input collected by receiver 52 is forwarded tocalibration unit 54 which analyzes the intensity of the motions. In thisapplication, calibration unit 54 consists of an audio level metersimilar to those used in stereophonic equipment. If an incoming signalreaches or exceeds a predetermined decibel value, the signal isqualified as a gross body movement, and a clean, conditioned signal issent to data processor 58 for compilation. The listing of the programfor data processor 58 appears at the end of the specification as anappendix and is written in a structured format (FORTRAN-77)understandable to those of ordinary skill in the art. Subject arousaldevice 62 is engaged directly from an annunciating port of dataprocessor 58 by way of line 60.

Referring to FIG. 3A there is shown the preferred embodiment of motionsensor 64 which may be contained within sensor bands 48. Motion sensor64 consists of a hard plastic, spherical shell or "bulb" 66 which issealed by plug 68 of similar material. This permits the implant ofirregularly shaped nuggets 70 within bulb 66. Nuggets 70 may consist ofsteel punching chips or similar material. A dynamic microphone 72 ismounted directly to the outer surface of hollow bulb 66, physicallyseparated by a small piece of acoustically transparent felt 74. Felt 74deadens sound which might result from microphone 72 rubbing against bulb66, thus, preventing these sounds from being interpreted as motions ofsubject 42. Microphone 72 is mounted on bulb 66 using a quick setting,molded epoxy cement 76. This mounting is, however, not the only meansfor microphone 72 attachment, as it might just as effectively be mountedwith bulb 66 by other means. Further, it should be noted that motionbulb 66 may be formed in any convenient size, as it will not affect theactual function of hardware system 40.

When a motion occurs, motion sensor 64 reacts in the following manner:As bulb 66 is displaced or translated nuggets or punching chips 70collide with each other and against the inside wall of bulb 66. Thisproduces a rattle-like sound which microphone 72 detects and, by way ofwire 73 relays to transmitter 75. Wire 73 is any 18-22 A.W.G. shieldedmicrophone cable or could equivalently be replaced by shielded coppercontacts if transmitter 75 is physically attached to bulb 66.Transmitter 75 comprises a radio transmitter of compact design poweredby a miniature battery or other conventional electric cell.

Circuitry used to transmit and calibrate the various levels of soundmeasurable by the system is described in 99 Practical ElectronicProjects, pg. 113; and similarly by a circuit disclosed in thepublication "Radio Electronics", November 1983, entitled "Build a VoiceOperated Switch for Your Tape Recorder." Additionally, circuitry andother details relevant to the present invention are described in "TheDream Retrieval System" by John Dilullo published at the AmericanSociety for Mechanical Engineering Convention in Atlanta, Georgia, June16, 1985, which is incorporated herewith by reference. However, anyconventional audio output meter would suffice. Radio waves are carriedfrom transmitter 75 by antenna 77 which may be a cylindrical conductoror simply a singular strand of 20 A.W.G. solid copper wire. Antenna 77may dangle freely from transmitter 75 or optionally may be sewn directlyinto sensor bands 48.

Referring to FIG. 3B there is shown band 48 which is the preferred meansof attaching motion sensor 64 to subject 42. Sensor band 48 consists ofa double pleated, flexible plastic strip 80 with a singular small cavity82. Cavity 82 snugly houses motion bulb 66. Band 48 wraps around forearm44 or calf 46 of subject 42 and may be fastened with institched Velcro84. This embodiment, however, is not the only method of attaching motionbulb 66 to subject 42. Motion bulb 66 may be sewn directly into thesubjects clothing or may alternately be affixed to the sleeping surface.

Referring to FIG. 4 there is shown system 10a which is a more detailedrepresentation of system 10. System 10a records, calibrates, andextrapolates the cyclic body motions which recur during human sleep.From these cyclic body motions, three subdivisions of dream sleep areidentified: pre-dream sleep, dream sleep, and post-dream sleep. With afew modifications, however, system 10a could comprise, in combination, adevice which applies many aspects of physiological behavior indetermining dream periods. Using conventional interfacing techniques thepresent invention could monitor and record, for example, electro-neuralactivity, respiration, rapid eye movements, muscle twitches, andperspiration.

In the present embodiment of system 10a the device is set to engage asuggester during a confirmed dream event and subsequently awaken thesubject following that dream event. Thus, system 10a functions as adream enhancement and retrieval system.

When system 10a is initially engaged, execution begins at initial block92 where system 10a assumes that subject 42 has just retired and willneed time to fall asleep. System 10a is not concerned with pre-sleepmotion and, therefore, at block 94 an arbitrary wait period is allocatedto allow subject 42 time to fall asleep. Furthermore, in the descriptionof start block 12 of system 10, numerous methods are described fordetermining when subject 42 is asleep. Block 94 is only executed oncebecause all exits and resetting transfers of execution are forwarded tostart block 96. Start block 96 differs from initial block 92 in that nodozing parameter is initiated. This is acceptable since at block 96subject 42 is already assumed to be sleeping.

When execution reaches start block 96, system 10a assumes that somewherewithin the body of the program conditions have warranted either an exitor a formal abort. Therefore, any flags which have been set or anycounts which have been registered, are no longer valid and are reset tozero. As set forth in paragraph three of the Appendix, this zeroingfunction is performed at block 98, where the flags and countingvariables are zeroed. In block 100 a determination is made whether amotion has occurred. Motion pulses are input from calibration unit 54and are in the form of an analog "1." When a valid motion is received,block 102 assigns an integer value of "1" to an element of the arrayMOVTAB, as set forth in paragraph seven of the listing.

The element number of MOVTAB is determined by the current time asobtained from block 106. When called, block 106 returns a three digitinteger value. This value is an expression, in minutes, of the currenttime, where, for example, the time at initial block 92 equals 000. Afterblock 106 is referenced execution always returns directly to thelocation where block 106 was called. The array MOVTAB is therefore atabulation of the evening's motion, where each element represents oneminute of sleep. Accordingly, each element of MOVTAB which contains aninteger value of "1" represents a particular minute of sleep wheresubject 42 had at least one gross body motion.

Since pre-dream sleep and post-dream sleep both share an increase ingross motor activity, at block 104 system 10a searches for motionflurries or clusters. A cluster is formally defined as a specifiednumber of motions occurring within a specified period of time. When boththe duration and count parameters are satisfied, a motion cluster isestablished. Typical parameters representative of a cluster are, forexample, four movements within eight minutes or three movements withinsix minutes. Here, the number of movements and the period of time couldbe easily manipulated to an individual's particular sleepingcharacteristics and peculiarities.

The analysis described in block 104 is executed in blocks 108 through112. Block 108 begins the retrospective analysis of the array MOVTAB formotion clusters. This process is performed by testing the last Nelements of the MOVTAB array. N equals the pre-specified time parameter,in minutes, of the duration of a typical motion cluster. When searchingfor motions indicative of pre-dream sleep, N equals the variable IPREPRin the Appendix whereas when searching for motions indicative ofpost-dream sleep N equals the variable IPOSPR as specified in paragraphseven of the Appendix. By way of line 109, block 110 examines the Ithelement of the MOVTAB array and determines when a motion has occurred.In this application I is an integer variable whose value increases by aninteger increment of 1 each time a new element of MOVTAB is referenced.I is initialized as the integer value of the current time, less thevalue of the duration parameter N. The loop is aborted when I reachesthe value of the current time. If, during this analysis, a specificelement of MOVTAB contains a motion, block 112 is referenced and thecurrent count is increased by one. Depicted in paragraph eight of thelisting, this process of sorting and accumulating is continued until thelast N elements of MOVTAB have been analyzed. After this, controlreturns to junction 105.

After analyzing MOVTAB for clusters, control is taken to block 114 byway of line 113. At block 114 a determination is made whether the numberof motions found in the last N elements of MOVTAB qualify as a clusterin accordance with the pre-determined time and count parameters. Thisprocess compares the current count to a pre-determined count variable X.X equals the integer value of the specified count parameter of a typicalmotion cluster. Pre-dream specifications denote X as equaling thevariable IPRCNT and post-dream specifications denote X as equaling thevariable IPOSCT, as set forth in paragraph eight of the listing. As isapparent, both N and X could easily be manipulated thus altering thequalifying parameters of a motion cluster and adding a method ofadjustability to system 10a.

If a group of motions from block 108 qualifies as a cluster asdetermined in block 14, an integer value of "1" is stored in the CYCLEarray at block 116. The CYCLE array appears equivalently in paragraphnine of the appendix as the array NCYCLE, however, its function isidentical. The element number of NCYCLE is determined by the integerrepresentation of the current time as obtained from block 106. Afterthis assignment, system 10a moves to junction 117. If it is determinedin block 114 that the count obtained in 108 is not sufficient toindicate a motion cluster, block 116 is bypassed and execution movesdirectly to junction 117. In either case, from junction 117 executionmoves to junction 119 and then to block 118 where the process ofanalyzing the NCYCLE array for recurrent clusters is initiated.

The NCYCLE array is analyzed with the following considerations:Pre-dream motion clusters are represented with an integer value 1 in therow dimension of the array while post-dream motion clusters arerepresented with an integer value 1 in the column dimension of thearray. When block 118 is referenced system 10a searches for 1's in theNCYCLE array. In addition since the NCYCLE array element numbers areassigned integer values equivalent to the time of their occurrence, ananalysis of the NCYCLE array 80-100 elements prior to the current timeat block 106 is performed. Thus a current dream event can be confirmedby determining that a cluster of motions preceded the current cluster ofmotions by an amount of time approximately equal to that of a dreamcycle.

In summary, block 118 initiates the search for an integer value of 1 inthe row dimension of NCYCLE. A 1 indicates a pre-dream motion cluster.Execution then sorts and accumulates 15-30 consecutive elements ofNCYCLE. If the final value of the accumulator is 0, no motion clustersappeared during the apparent dream period, thus confirming a period ofrelative immobility. Next, NCYCLE is searched for an integer value of 1in the column dimension. If found, post-dream behavior is confirmed andan apparent dream event has been observed. A similar occurrence will besearched for the NCYCLE array 80-100 elements past the row element whichinitially indicated pre-dream motion. This search for recurrence is setforth by the listing in paragraph nine.

To determine whether initial or recurrent behavior is being monitored, aflag system is used. Each time dream behavior is noted at block 128 theflag is increased by an integer value of 1 and, similarly, each timepost-dream behavior is noted at block 136 the flag is increased by aninteger value of 1. Hence, after the first run through the loop, if bothpre-dream and post-dream conditions are noted, the flag equals theinteger value 2. If the dreaming condition is confirmed again the flagwill increase to 3. Thus, the purpose of the decisions at blocks 124 and134 is to determine whether recurrent behavior is being observed.

Similar to the procedure in block 14 of system 10, block 120 determineswhether subject 42 is experiencing motion behavior indicative ofpre-dream sleep. When an integer value of 1 is found in the rowdimension of the NCYCLE array a pre-dream condition is confirmed. But,if the conditions at block 120 are not satisfied, control moves to block122 where an exit is encountered and execution is subsequentlytransferred to start block 96. If, however, the conditions mentionedabove are established in block 120, execution moves to block 124 where adetermination is made whether the flag equals the integer value 2. Ifthe flag equals the integer value 2 then a recurrence of pre-dream sleephas been observed and the suggester of block 126 may optionally beengaged. Subsequently, when the flag equals some integer value less than2 the following deduction is made: no previous flags have been set andthis pre-dream condition is without confirmation. Therefore, this is notrecurrent behavior and the suggester at block 126 is not engaged.Instead, execution is transferred directly to junction 127.

Whatever the determination of block 124, control moves to junction 127and then to block 128. At block 128 a determination is made whether thesubject is demonstrating a positive dreaming condition. This conditionis satisfied if no movement clusters appear during the approximate dreamperiod. Or equivalently, if no integer values appear in the row orcolumn dimension of the NCYCLE array. In this case, the dream periodparameter is approximately 15-30 elements long and is adjustable bymanipulating the variable LENGTH, as shown in paragraph nine of thelisting. When dream conditions are observed at block 128, the flag isincreased by 1 at block 132. If, however, the above conditions are notsatisfied, the loop is exited at block 130 and execution is returned tostart block 96.

After the flag has been increased at block 132, a determination is madeat block 134 whether the flag equals the integer value 3. If the flagdoes not equal the integer value 3, the subject is experiencing anapparent dream event without confirmation, as in block 20 of system 10.This does not warrant the activation of subject stimuli. Hence, by wayof line 135, execution moves to block 136 where a determination is madewhether a positive post-dream condition is apparent. If post-dreammotion is observed, the flag is increased by 1 and execution moves tojunction 119. Since the flag now equals the integer value 2, when block118 is again executed the NCYCLE array will be referenced in a time slotwhich is 80-100 minutes greater than when the preceding analysisoccurred. The references to the NCYCLE array elements are increased byan integer value between 80 and 100. Since all references made to block118 are retrospective this confirmation technique references the NCYCLEarray to determine what subject motion occurred over the last 80-100minutes. Therefore, if execution determines negative conditions inblocks 120 and 128, execution returns to start block 96 and MOVTABvalues are again assigned. PG,27

Referring again to the decision of block 134, if the flag is equal tothe integer value 3, a recurrence is established, and system 10a isevidently analyzing the recurrence of an earlier pattern. Thus, by wayof line 137, a wakeup parameter is set at block 142. This wakeupparameter establishes an allowable period during which system 10a couldconfirm the apparent dream event. By referencing block 100 andincorporating the AND gate of block 144, the following condition isestablished: If a motion is detected, and the wakeup parameter of block142 is still engaged, the alarm is sounded at block 146. Thus awakeningsubject 42 and carrying out the present invention on the firstpost-dream motion of subject 42. If, however, the wakeup parameterexpires before a motion is detected, execution returns to start block96, as shown in paragraph four of the listing.

The operation of dream retrieval system 10a is now described withrespect to the control and sequencing of data processor 58 of system 40.The listing for the program for microprocessor 58 appears at the end ofthe specification as an Appendix and is written in standard FORTRAN-77understandable by those of ordinary skill in the art. The program beginswith variable declarations and sequentially executes all the necessarydeductions and functions set forth in system 10a. The main program canbe compiled on any computational device which supports FORTRAN-77 andhas at least one analog Input/Output conversion port. However, the timeconversion subroutine, set forth in the paragraph ten of the listing, isunique to the Digital Equipment Corporation VAX 11/780 under Vms. 3.0system software and may require alteration for usage on other systems.

Although the invention has been particularly shown and described withreference to a preferred embodiment thereof, it will be understood bythose skilled in the art, that various changes may be made thereinwithout departing from the spirit or scope of the invention. ##SPC1##

I claim:
 1. A method for confirming the occurrence of dream behaviorparameters in a sleeping subject having dream cycles comprising thesteps of:(a) detecting a first occurrence of dream behavior parameters;(b) establishing a predetermined time period after the detection of thefirst occurrence, the duration of the time period being related to theduration of a dream cycle; (c) determining the substantial absence ofdream behavior parameters during the predetermined time period; (d)detecting a second occurrence of dream behavior parameters after thepredetermined time period; and (e) confirming the occurrence of a dreamonly in response to said determination and second occurrence.
 2. Themethod of claim 1 in which step (d) includes the steps of establishing atime window of predetermined duration beginning at the end of thepredetermined time period and confirming the occurrence of a dream onlyin response to the second occurrence during the window.
 3. The method ofclaim 1 including the additional step of awakening the subject afterconfirming the occurrence of a dream.
 4. The method of claim 1 in whichsteps (a) and (d) include detecting gross body motion.
 5. The method ofclaim 4 in which the step of detecting gross body motion includesdetecting a predetermined number of body motions within a predeterminedperiod of time.
 6. The method of claim 4 in which the step of detectinggross body motion comprises:(a) rustling nuggets in response to grossbody motion; and (b) converting into electrical energy acoustical energyproduced by impacts between the rustled nuggets.
 7. The method of claim1 in which steps (a) and (d) include detecting a plurality of differentdream behavior parameters.
 8. A system for confirming the occurrence ofdream behavior parameters in a sleeping subject having dream cyclescomprising:(a) means for detecting a first occurrence of dream behaviorparameters; (b) means for establishing a predetermined time period afterthe detection of the first occurrence, the duration of the time periodbeing related to the duration of a dream cycle; (c) means for detectinga second occurrence of dream behavior parameters after the predeterminedtime period; and (d) means for confirming the occurrence of a dream onlyin response to said second occurrence.